Another vote for having the developers and DBAs to be working side by side in the same team.

So divisional teams based around products with a single manager for both. Functional teams produce experts very good at implementing policy (eg security) but can lack in practical implementation of usable products.

A lot of the time I think it comes down to aligning the motivation of the individuals to the task at hand.

There will be times when you have to go quick and dirty. Having developer and dbas working closely together in my opinion lends itself to compromise and flexibility much better which I think usually ends up with a better end result.

Sitting in the same office you sometimes overhear things and if its serious you can jump in and say - guys that is going to cause some other problems how about this alternative.